The invention relates to a device and a method for the study and modification of the properties near surfaces and of surfaces of different types of materials. The device and method are utilized in the context of an atomic force microscope (AFM).
The AFM method is a commonly deployed method in industry and research to scan a surface with the aid of a very sharp measurement tip. The measurement tip is located at the unsupported end of a micromechanical cantilever and reacts to short-ranged (van der Waals) forces. The AFM method is frequently deployed in the areas of surface physics, molecular biology, pharmacology, the material sciences, and nano technology. Furthermore AFMs are utilized in industry on the one hand for process control, but also increasingly for the study of novel phenomena that play an increasingly important role, because of the progressing miniaturization, in the context of the manufacture and use of highly integrated circuits. Among these are plasmonic resonances and the scattering behavior of polaritons bound to the surface. These are a key element for high-frequency circuits on the nanometer scale.
A further method that is based on AFM—optical near field microscopy (SNOM—scanning near field optical microscopy)—utilizes light which is guided through a light-permeable opening in the measurement tip onto the surface to be studied and which is analyzed by means of an interferometer or a photo detector located a small distance behind the transparent sample. This method exclusively utilizes—due to its operating principle—light that can be guided through suitable media (for example glass fibers). Known methods of atomic force microscopy primarily include:                the contact mode (contact mode), in which the measurement tip is in contact with the surface and is moved at a constant support force across the same.        the contact-less mode, in which the cantilever is sent into oscillations and the amplitude and phase of these oscillations are measured and controlled so that a contactless interaction with the surface occurs. This mode provides topological information.        the shear force mode (shear force), in which oscillations of the measurement tip are measured parallel to the surface.        
The two last-mentioned AFM-methods offer the advantage that for scanning no inelastic, electronic exchange effect with the surface is necessary and therefore biological and non- or semi-conducting surfaces can also be measured. Besides that, the known methods of optical near field microscopy (SNOM-scanning near field optical microscopy) are also used for the study of biological samples. However because of the coupling of AFM principle and optical detection, they only offer limited possibilities for the chemical and electronic identification of the surface. Most often in molecular biology special marking atoms or molecules are used that feature fluorescence in an accessible wavelength range. This useable wavelength range is significantly limited, however, due to its principle of operation.
In fundamental research an optical method has been demonstrated that employs a passive, metallic structure in order to excite plasmonic resonances [Publication by J. N. Farahani, D. W. Pohl, H.-J. Eisler and B. Hecht in Physical Review Letters 95, 017402 (2005)]. In this context light is guided by means of conventional optics from the side facing away from the cantilever to the sample and analyzed. Because of its shape, the cantilever serves as a passive antenna that is tuned to the structures under study.
The focusing of synchrotron or laser radiation onto extremely small (a few nanometers diameter) controllable areas of a sample to be studied has previously not been possible because of the absence of suitable optics. Because of the extremely high intensity and parallelness such small dimensions can nonetheless be achieved by the present invention with synchrotron light.
DE 103 07 561 A1 shows a measurement arrangement for combined scanning and studying of construction components that feature micro-technical, electrical contacts that is particularly suitable for all three methods that were described above. Thereby the otherwise commonly used laser optics for the readout of the bending or the oscillation amplitude and phase can be omitted entirely. This task is taken over by a heating wire (thermal bimorph actuator) that is integrated into the cantilever along with an integrated piezo-resistive resistor network. This method and such atomic force probes (piezo-resistive cantilever) with integrated bimorph actuator and differently functionalized measurement tips are described in I. W. Rangelow: “Piezoresistive Scanning Proximity Probes for Nanoscience”, Technisches Messen (Technical Measurement) 72 (2005) 2, page 103-110].
Due to their operating principles, the known AFM methods have the disadvantage of not providing chemical or electronic information about the surface. The SNOM methods are limited to the wavelength range of transmission through glass fibers and require the AFM signal for the measurement, the utilization of molecular substances can falsify the investigational result a priori. The above-mentioned method of Farahani also has the disadvantage of being dependent on semi-transparent samples. The nanoscopic antenna is passive, non-contacting and therefore not configurable. The antenna cannot adapt itself to different sample conditions.
It is therefore the purpose of the present invention to overcome these key problems of the devices and methods previously used.